                a) Field of the Invention        
The present invention relates to an improved structure of a saxophone windpipe, particularly to replace the conventional spring plate with a spiral spring to reduce hole drilling and screwing action, thus simplifying the structure and production process, achieving decrease in capital of the windpipe structure.                b) Description of the Prior Art        
The saxophone used in jazz music is primary formed by a saxophone wind tube, a mouth-pipe and a mouth. Wooden pieces are installed on the mouth. By blowing the pieces to vibrate, sound will be emitted.
Referring to FIG. 4, a high pitch hole a1 and a tube seat a2 is installed on a mouth-tube. Further, a middle part of an operating rod b has two sides protruding downwards where an ear seat b1 is formed, enabling the operating rod b and a tube seat a2 on the mouth-tube a to connect. A spring plate c is assembled on a lower end of the operating rod b; the lower portion of the spring plate c is leaned against the mouth-tube a. A key cover b2 is formed on an inner tip of the operating rod b, moreover, a guide seat a3 is installed on an upper portion of the mouth-tube a in front of a high pitch hole a1, thus the operating rod b is supported by the guide seat a3, enabling the key cover b2 to press on the high pitch hole a1. Further, a ring cover b3 is formed on a lower portion of the operating rod b, encircling a lower portion of the mouth-tube a, moreover, a push rod d2 connecting a high pitch key d1 is assembled on an upper portion of a saxophone wind tube d; the push rod d2 is leaned against the inner side of the ring cover b3. Thus, by pressing the high pitch key d1, the push rod d2 will push the operating rod a1; thereby the key cover b2 on the upper portion of the operating rod b is no longer pressed on the high pitch hole a1, emitting a high pitch. When the high pitch key d1 is released, the operating rod b will move back to its original position by the spring plate c1, enabling the key cover b2 on the operating rod b to be pressed against the high pitch hole a1, emitting a low pitch.
Moreover, the aforesaid spring plate c is screwed on the operating rod b by drilling a hole on an inner side of the operating rod b and a hole on a side of the spring plate c. Before the spring plate c is installed, the spring plate c is bent into an arc shape to a fixed angle to maintain stableness of tension. The process of production is complex, and the stability is difficult to control. Furthermore, the spring plate loses its flexibility after a period of time; thereby in conclusion to the above, the conventional structure of wind tube is fairly complicated, and process of production is complex, thus, capital is increased enabling decrease in market competition.